Perry's Index to the Aesopica

Fables exist in many versions; here is one version in English:

THE DONKEY AND HIS MASTERS

There was a donkey who worked for a gardener. Because the gardener made the
donkey work very hard but gave him very little food, the donkey prayed to Zeus
to take him away from the gardener and give him to another master, so Zeus sent
Hermes to sell the donkey to a potter. The donkey also found this situation
unbearable, since he was forced to carry even heavier loads than before. He
called upon Zeus again, and this time Zeus arranged for the donkey to be purchased
by a tanner. When the donkey saw the kind of work the tanner did, he said, 'Oh,
it would have been better for me to have kept on working for my previous masters
in a state of starvation! Now I have ended up in a place where I won't even
get a proper burial after I die.' The story shows that slaves miss their former masters the most when they
have had some experience with their new ones.

Source:
Aesop's Fables. A new translation by Laura
Gibbs.
Oxford University Press (World's Classics): Oxford, 2002.
NOTE: New
cover, with new ISBN, published in 2008; contents of book unchanged.

You can find a compilation of Perry's index to the Aesopica in the gigantic appendix to his
edition of Babrius and Phaedrus for the Loeb Classical Library
(Harvard University Press: Cambridge, 1965). This book is an absolute must for anyone interested
in the Aesopic fable tradition. Invaluable.